D-aspartic acid, often abbreviated to DAA, is an amino acid which is important in the synthesis of the hormone testosterone. D-aspartic acid is concentrated in the cartilage, brain and red blood cell membranes. It functions as a neurotransmitter in the brain.
Preliminary animal studies have shown that DAA, when taken orally as a supplement, may help to enhance memory and cognitive function; however no human studies have been done on this yet.
Human studies have consistently shown, however, that DAA taken as a supplement does increase testosterone production in healthy men. This appears to be a temporary boost, but the effects can last up to one and a half weeks.
For this reason, d-aspartic acid or DAA is a popular fitness or athletic supplement. Athletes opt to increase testosterone levels for a variety of reasons, not least because testosterone plays a role in building muscle mass. Testosterone also increases athletic endurance and helps to redistribute body fat more effectively and efficiently. Finally, testosterone is thought to aid muscle and bone repair following stress or injury.
DAA is also taken by those wishing to enhance libido or male sexual performance. DAA can be found naturally in foods such as oysters, poultry, red meat and eggs. As a supplement, it is available in powder or tablet/capsule format.